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A copy of the license is included in the section entitled +"GNU Free Documentation License". + + <p>(a) The FSF's Front-Cover Text is: + + <p>A GNU Manual + + <p>(b) The FSF's Back-Cover Text is: + + <p>You have freedom to copy and modify this GNU Manual, like GNU + software. Copies published by the Free Software Foundation raise + funds for GNU development.--> +<meta http-equiv="Content-Style-Type" content="text/css"> +<style type="text/css"><!-- + pre.display { font-family:inherit } + pre.format { font-family:inherit } + pre.smalldisplay { font-family:inherit; font-size:smaller } + pre.smallformat { font-family:inherit; font-size:smaller } + pre.smallexample { font-size:smaller } + pre.smalllisp { font-size:smaller } +--></style> +</head> +<body> +<h1 class="settitle">Porting libstdc++</h1> +<div class="node"> +<p><hr> +Node: <a name="Top">Top</a>, +Next: <a rel="next" accesskey="n" href="#Operating%20system">Operating system</a>, +Up: <a rel="up" accesskey="u" href="#dir">(dir)</a> +<br> +</div> + +<h2 class="unnumbered">Porting libstdc++</h2> + +<p>This document explains how to port libstdc++ (the GNU C++ library) to +a new target. + + <p>In order to make the GNU C++ library (libstdc++) work with a new +target, you must edit some configuration files and provide some new +header files. Unless this is done, libstdc++ will use generic +settings which may not be correct for your target; even if they are +correct, they will likely be inefficient. + + <p>Before you get started, make sure that you have a working C library on +your target. The C library need not precisely comply with any +particular standard, but should generally conform to the requirements +imposed by the ANSI/ISO standard. + + <p>In addition, you should try to verify that the C++ compiler generally +works. It is difficult to test the C++ compiler without a working +library, but you should at least try some minimal test cases. + + <p>(Note that what we think of as a "target," the library refers to as +a "host." The comment at the top of <code>configure.ac</code> explains why.) + + <p>Here are the primary steps required to port the library: + +<ul class="menu"> +<li><a accesskey="1" href="#Operating%20system">Operating system</a>: Configuring for your operating system. +<li><a accesskey="2" href="#CPU">CPU</a>: Configuring for your processor chip. +<li><a accesskey="3" href="#Character%20types">Character types</a>: Implementing character classification. +<li><a accesskey="4" href="#Thread%20safety">Thread safety</a>: Implementing atomic operations. +<li><a accesskey="5" href="#Numeric%20limits">Numeric limits</a>: Implementing numeric limits. +<li><a accesskey="6" href="#Libtool">Libtool</a>: Using libtool. +<li><a accesskey="7" href="#GNU%20Free%20Documentation%20License">GNU Free Documentation License</a>: How you can copy and share this manual. +</ul> + +<div class="node"> +<p><hr> +Node: <a name="Operating%20system">Operating system</a>, +Next: <a rel="next" accesskey="n" href="#CPU">CPU</a>, +Previous: <a rel="previous" accesskey="p" href="#Top">Top</a>, +Up: <a rel="up" accesskey="u" href="#Top">Top</a> +<br> +</div> + +<h2 class="chapter">Operating system</h2> + +<p>If you are porting to a new operating system (as opposed to a new chip +using an existing operating system), you will need to create a new +directory in the <code>config/os</code> hierarchy. For example, the IRIX +configuration files are all in <code>config/os/irix</code>. There is no set +way to organize the OS configuration directory. For example, +<code>config/os/solaris/solaris-2.6</code> and +<code>config/os/solaris/solaris-2.7</code> are used as configuration +directories for these two versions of Solaris. On the other hand, both +Solaris 2.7 and Solaris 2.8 use the <code>config/os/solaris/solaris-2.7</code> +directory. The important information is that there needs to be a +directory under <code>config/os</code> to store the files for your operating +system. + + <p>You might have to change the <code>configure.host</code> file to ensure that +your new directory is activated. Look for the switch statement that sets +<code>os_include_dir</code>, and add a pattern to handle your operating system +if the default will not suffice. The switch statement switches on only +the OS portion of the standard target triplet; e.g., the <code>solaris2.8</code> +in <code>sparc-sun-solaris2.8</code>. If the new directory is named after the +OS portion of the triplet (the default), then nothing needs to be changed. + + <p>The first file to create in this directory, should be called +<code>os_defines.h</code>. This file contains basic macro definitions +that are required to allow the C++ library to work with your C library. + + <p>Several libstdc++ source files unconditionally define the macro +<code>_POSIX_SOURCE</code>. On many systems, defining this macro causes +large portions of the C library header files to be eliminated +at preprocessing time. Therefore, you may have to <code>#undef</code> this +macro, or define other macros (like <code>_LARGEFILE_SOURCE</code> or +<code>__EXTENSIONS__</code>). You won't know what macros to define or +undefine at this point; you'll have to try compiling the library and +seeing what goes wrong. If you see errors about calling functions +that have not been declared, look in your C library headers to see if +the functions are declared there, and then figure out what macros you +need to define. You will need to add them to the +<code>CPLUSPLUS_CPP_SPEC</code> macro in the GCC configuration file for your +target. It will not work to simply define these macros in +<code>os_defines.h</code>. + + <p>At this time, there are a few libstdc++-specific macros which may be +defined: + + <p><code>_GLIBCXX_USE_C99_CHECK</code> may be defined to 1 to check C99 +function declarations (which are not covered by specialization below) +found in system headers against versions found in the library headers +derived from the standard. + + <p><code>_GLIBCXX_USE_C99_DYNAMIC</code> may be defined to an expression that +yields 0 if and only if the system headers are exposing proper support +for C99 functions (which are not covered by specialization below). If +defined, it must be 0 while bootstrapping the compiler/rebuilding the +library. + + <p><code>_GLIBCXX_USE_C99_LONG_LONG_CHECK</code> may be defined to 1 to check +the set of C99 long long function declarations found in system headers +against versions found in the library headers derived from the +standard. + + <p><code>_GLIBCXX_USE_C99_LONG_LONG_DYNAMIC</code> may be defined to an +expression that yields 0 if and only if the system headers are +exposing proper support for the set of C99 long long functions. If +defined, it must be 0 while bootstrapping the compiler/rebuilding the +library. + + <p><code>_GLIBCXX_USE_C99_FP_MACROS_DYNAMIC</code> may be defined to an +expression that yields 0 if and only if the system headers +are exposing proper support for the related set of macros. If defined, +it must be 0 while bootstrapping the compiler/rebuilding the library. + + <p><code>_GLIBCXX_USE_C99_FLOAT_TRANSCENDENTALS_CHECK</code> may be defined +to 1 to check the related set of function declarations found in system +headers against versions found in the library headers derived from +the standard. + + <p><code>_GLIBCXX_USE_C99_FLOAT_TRANSCENDENTALS_DYNAMIC</code> may be defined +to an expression that yields 0 if and only if the system headers +are exposing proper support for the related set of functions. If defined, +it must be 0 while bootstrapping the compiler/rebuilding the library. + + <p>Finally, you should bracket the entire file in an include-guard, like +this: + +<pre class="example"> #ifndef _GLIBCXX_OS_DEFINES + #define _GLIBCXX_OS_DEFINES + ... + #endif + </pre> + + <p>We recommend copying an existing <code>os_defines.h</code> to use as a +starting point. + +<div class="node"> +<p><hr> +Node: <a name="CPU">CPU</a>, +Next: <a rel="next" accesskey="n" href="#Character%20types">Character types</a>, +Previous: <a rel="previous" accesskey="p" href="#Operating%20system">Operating system</a>, +Up: <a rel="up" accesskey="u" href="#Top">Top</a> +<br> +</div> + +<h2 class="chapter">CPU</h2> + +<p>If you are porting to a new chip (as opposed to a new operating system +running on an existing chip), you will need to create a new directory in the +<code>config/cpu</code> hierarchy. Much like the <a href="#Operating%20system">Operating system</a> setup, +there are no strict rules on how to organize the CPU configuration +directory, but careful naming choices will allow the configury to find your +setup files without explicit help. + + <p>We recommend that for a target triplet <code><CPU>-<vendor>-<OS></code>, you +name your configuration directory <code>config/cpu/<CPU></code>. If you do this, +the configury will find the directory by itself. Otherwise you will need to +edit the <code>configure.host</code> file and, in the switch statement that sets +<code>cpu_include_dir</code>, add a pattern to handle your chip. + + <p>Note that some chip families share a single configuration directory, for +example, <code>alpha</code>, <code>alphaev5</code>, and <code>alphaev6</code> all use the +<code>config/cpu/alpha</code> directory, and there is an entry in the +<code>configure.host</code> switch statement to handle this. + + <p>The <code>cpu_include_dir</code> sets default locations for the files controlling +<a href="#Thread%20safety">Thread safety</a> and <a href="#Numeric%20limits">Numeric limits</a>, if the defaults are not +appropriate for your chip. + +<div class="node"> +<p><hr> +Node: <a name="Character%20types">Character types</a>, +Next: <a rel="next" accesskey="n" href="#Thread%20safety">Thread safety</a>, +Previous: <a rel="previous" accesskey="p" href="#CPU">CPU</a>, +Up: <a rel="up" accesskey="u" href="#Top">Top</a> +<br> +</div> + +<h2 class="chapter">Character types</h2> + +<p>The library requires that you provide three header files to implement +character classification, analogous to that provided by the C libraries +<code><ctype.h></code> header. You can model these on the files provided in +<code>config/os/generic</code>. However, these files will almost +certainly need some modification. + + <p>The first file to write is <code>ctype_base.h</code>. This file provides +some very basic information about character classification. The libstdc++ +library assumes that your C library implements <code><ctype.h></code> by using +a table (indexed by character code) containing integers, where each of +these integers is a bit-mask indicating whether the character is +upper-case, lower-case, alphabetic, etc. The <code>ctype_base.h</code> +file gives the type of the integer, and the values of the various bit +masks. You will have to peer at your own <code><ctype.h></code> to figure out +how to define the values required by this file. + + <p>The <code>ctype_base.h</code> header file does not need include guards. +It should contain a single <code>struct</code> definition called +<code>ctype_base</code>. This <code>struct</code> should contain two type +declarations, and one enumeration declaration, like this example, taken +from the IRIX configuration: + +<pre class="example"> struct ctype_base + { + typedef unsigned int mask; + typedef int* __to_type; + + enum + { + space = _ISspace, + print = _ISprint, + cntrl = _IScntrl, + upper = _ISupper, + lower = _ISlower, + alpha = _ISalpha, + digit = _ISdigit, + punct = _ISpunct, + xdigit = _ISxdigit, + alnum = _ISalnum, + graph = _ISgraph + }; + }; + </pre> + +<p>The <code>mask</code> type is the type of the elements in the table. If your +C library uses a table to map lower-case numbers to upper-case numbers, +and vice versa, you should define <code>__to_type</code> to be the type of the +elements in that table. If you don't mind taking a minor performance +penalty, or if your library doesn't implement <code>toupper</code> and +<code>tolower</code> in this way, you can pick any pointer-to-integer type, +but you must still define the type. + + <p>The enumeration should give definitions for all the values in the above +example, using the values from your native <code><ctype.h></code>. They can +be given symbolically (as above), or numerically, if you prefer. You do +not have to include <code><ctype.h></code> in this header; it will always be +included before <code>ctype_base.h</code> is included. + + <p>The next file to write is <code>ctype_noninline.h</code>, which also does +not require include guards. This file defines a few member functions +that will be included in <code>include/bits/locale_facets.h</code>. The first +function that must be written is the <code>ctype<char>::ctype</code> +constructor. Here is the IRIX example: + +<pre class="example"> ctype<char>::ctype(const mask* __table = 0, bool __del = false, + size_t __refs = 0) + : _Ctype_nois<char>(__refs), _M_del(__table != 0 && __del), + _M_toupper(NULL), + _M_tolower(NULL), + _M_ctable(NULL), + _M_table(!__table + ? (const mask*) (__libc_attr._ctype_tbl->_class + 1) + : __table) + { } + </pre> + +<p>There are two parts of this that you might choose to alter. The first, +and most important, is the line involving <code>__libc_attr</code>. That is +IRIX system-dependent code that gets the base of the table mapping +character codes to attributes. You need to substitute code that obtains +the address of this table on your system. If you want to use your +operating system's tables to map upper-case letters to lower-case, and +vice versa, you should initialize <code>_M_toupper</code> and +<code>_M_tolower</code> with those tables, in similar fashion. + + <p>Now, you have to write two functions to convert from upper-case to +lower-case, and vice versa. Here are the IRIX versions: + +<pre class="example"> char + ctype<char>::do_toupper(char __c) const + { return _toupper(__c); } + + char + ctype<char>::do_tolower(char __c) const + { return _tolower(__c); } + </pre> + +<p>Your C library provides equivalents to IRIX's <code>_toupper</code> and +<code>_tolower</code>. If you initialized <code>_M_toupper</code> and +<code>_M_tolower</code> above, then you could use those tables instead. + + <p>Finally, you have to provide two utility functions that convert strings +of characters. The versions provided here will always work - but you +could use specialized routines for greater performance if you have +machinery to do that on your system: + +<pre class="example"> const char* + ctype<char>::do_toupper(char* __low, const char* __high) const + { + while (__low < __high) + { + *__low = do_toupper(*__low); + ++__low; + } + return __high; + } + + const char* + ctype<char>::do_tolower(char* __low, const char* __high) const + { + while (__low < __high) + { + *__low = do_tolower(*__low); + ++__low; + } + return __high; + } + </pre> + + <p>You must also provide the <code>ctype_inline.h</code> file, which +contains a few more functions. On most systems, you can just copy +<code>config/os/generic/ctype_inline.h</code> and use it on your system. + + <p>In detail, the functions provided test characters for particular +properties; they are analogous to the functions like <code>isalpha</code> and +<code>islower</code> provided by the C library. + + <p>The first function is implemented like this on IRIX: + +<pre class="example"> bool + ctype<char>:: + is(mask __m, char __c) const throw() + { return (_M_table)[(unsigned char)(__c)] & __m; } + </pre> + +<p>The <code>_M_table</code> is the table passed in above, in the constructor. +This is the table that contains the bitmasks for each character. The +implementation here should work on all systems. + + <p>The next function is: + +<pre class="example"> const char* + ctype<char>:: + is(const char* __low, const char* __high, mask* __vec) const throw() + { + while (__low < __high) + *__vec++ = (_M_table)[(unsigned char)(*__low++)]; + return __high; + } + </pre> + +<p>This function is similar; it copies the masks for all the characters +from <code>__low</code> up until <code>__high</code> into the vector given by +<code>__vec</code>. + + <p>The last two functions again are entirely generic: + +<pre class="example"> const char* + ctype<char>:: + scan_is(mask __m, const char* __low, const char* __high) const throw() + { + while (__low < __high && !this->is(__m, *__low)) + ++__low; + return __low; + } + + const char* + ctype<char>:: + scan_not(mask __m, const char* __low, const char* __high) const throw() + { + while (__low < __high && this->is(__m, *__low)) + ++__low; + return __low; + } + </pre> + +<div class="node"> +<p><hr> +Node: <a name="Thread%20safety">Thread safety</a>, +Next: <a rel="next" accesskey="n" href="#Numeric%20limits">Numeric limits</a>, +Previous: <a rel="previous" accesskey="p" href="#Character%20types">Character types</a>, +Up: <a rel="up" accesskey="u" href="#Top">Top</a> +<br> +</div> + +<h2 class="chapter">Thread safety</h2> + +<p>The C++ library string functionality requires a couple of atomic +operations to provide thread-safety. If you don't take any special +action, the library will use stub versions of these functions that are +not thread-safe. They will work fine, unless your applications are +multi-threaded. + + <p>If you want to provide custom, safe, versions of these functions, there +are two distinct approaches. One is to provide a version for your CPU, +using assembly language constructs. The other is to use the +thread-safety primitives in your operating system. In either case, you +make a file called <code>atomicity.h</code>, and the variable +<code>ATOMICITYH</code> must point to this file. + + <p>If you are using the assembly-language approach, put this code in +<code>config/cpu/<chip>/atomicity.h</code>, where chip is the name of +your processor (see <a href="#CPU">CPU</a>). No additional changes are necessary to +locate the file in this case; <code>ATOMICITYH</code> will be set by default. + + <p>If you are using the operating system thread-safety primitives approach, +you can also put this code in the same CPU directory, in which case no more +work is needed to locate the file. For examples of this approach, +see the <code>atomicity.h</code> file for IRIX or IA64. + + <p>Alternatively, if the primitives are more closely related to the OS +than they are to the CPU, you can put the <code>atomicity.h</code> file in +the <a href="#Operating%20system">Operating system</a> directory instead. In this case, you must +edit <code>configure.host</code>, and in the switch statement that handles +operating systems, override the <code>ATOMICITYH</code> variable to point to +the appropriate <code>os_include_dir</code>. For examples of this approach, +see the <code>atomicity.h</code> file for AIX. + + <p>With those bits out of the way, you have to actually write +<code>atomicity.h</code> itself. This file should be wrapped in an +include guard named <code>_GLIBCXX_ATOMICITY_H</code>. It should define one +type, and two functions. + + <p>The type is <code>_Atomic_word</code>. Here is the version used on IRIX: + +<pre class="example"> typedef long _Atomic_word; + </pre> + +<p>This type must be a signed integral type supporting atomic operations. +If you're using the OS approach, use the same type used by your system's +primitives. Otherwise, use the type for which your CPU provides atomic +primitives. + + <p>Then, you must provide two functions. The bodies of these functions +must be equivalent to those provided here, but using atomic operations: + +<pre class="example"> static inline _Atomic_word + __attribute__ ((__unused__)) + __exchange_and_add (_Atomic_word* __mem, int __val) + { + _Atomic_word __result = *__mem; + *__mem += __val; + return __result; + } + + static inline void + __attribute__ ((__unused__)) + __atomic_add (_Atomic_word* __mem, int __val) + { + *__mem += __val; + } + </pre> + +<div class="node"> +<p><hr> +Node: <a name="Numeric%20limits">Numeric limits</a>, +Next: <a rel="next" accesskey="n" href="#Libtool">Libtool</a>, +Previous: <a rel="previous" accesskey="p" href="#Thread%20safety">Thread safety</a>, +Up: <a rel="up" accesskey="u" href="#Top">Top</a> +<br> +</div> + +<h2 class="chapter">Numeric limits</h2> + +<p>The C++ library requires information about the fundamental data types, +such as the minimum and maximum representable values of each type. +You can define each of these values individually, but it is usually +easiest just to indicate how many bits are used in each of the data +types and let the library do the rest. For information about the +macros to define, see the top of <code>include/bits/std_limits.h</code>. + + <p>If you need to define any macros, you can do so in <code>os_defines.h</code>. +However, if all operating systems for your CPU are likely to use the +same values, you can provide a CPU-specific file instead so that you +do not have to provide the same definitions for each operating system. +To take that approach, create a new file called <code>cpu_limits.h</code> in +your CPU configuration directory (see <a href="#CPU">CPU</a>). + +<div class="node"> +<p><hr> +Node: <a name="Libtool">Libtool</a>, +Next: <a rel="next" accesskey="n" href="#GNU%20Free%20Documentation%20License">GNU Free Documentation License</a>, +Previous: <a rel="previous" accesskey="p" href="#Numeric%20limits">Numeric limits</a>, +Up: <a rel="up" accesskey="u" href="#Top">Top</a> +<br> +</div> + +<h2 class="chapter">Libtool</h2> + +<p>The C++ library is compiled, archived and linked with libtool. +Explaining the full workings of libtool is beyond the scope of this +document, but there are a few, particular bits that are necessary for +porting. + + <p>Some parts of the libstdc++ library are compiled with the libtool +<code>--tags CXX</code> option (the C++ definitions for libtool). Therefore, +<code>ltcf-cxx.sh</code> in the top-level directory needs to have the correct +logic to compile and archive objects equivalent to the C version of libtool, +<code>ltcf-c.sh</code>. Some libtool targets have definitions for C but not +for C++, or C++ definitions which have not been kept up to date. + + <p>The C++ run-time library contains initialization code that needs to be +run as the library is loaded. Often, that requires linking in special +object files when the C++ library is built as a shared library, or +taking other system-specific actions. + + <p>The libstdc++ library is linked with the C version of libtool, even +though it is a C++ library. Therefore, the C version of libtool needs to +ensure that the run-time library initializers are run. The usual way to +do this is to build the library using <code>gcc -shared</code>. + + <p>If you need to change how the library is linked, look at +<code>ltcf-c.sh</code> in the top-level directory. Find the switch statement +that sets <code>archive_cmds</code>. Here, adjust the setting for your +operating system. + +<div class="node"> +<p><hr> +Node: <a name="GNU%20Free%20Documentation%20License">GNU Free Documentation License</a>, +Previous: <a rel="previous" accesskey="p" href="#Libtool">Libtool</a>, +Up: <a rel="up" accesskey="u" href="#Top">Top</a> +<br> +</div> + +<h2 class="unnumbered">GNU Free Documentation License</h2> + +<div align="center">Version 1.2, November 2002</div> +<pre class="display"> Copyright © 2000,2001,2002 Free Software Foundation, Inc. + 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA + + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + </pre> + + <ol type=1 start=0> +<li>PREAMBLE + + <p>The purpose of this License is to make a manual, textbook, or other +functional and useful document <dfn>free</dfn> in the sense of freedom: to +assure everyone the effective freedom to copy and redistribute it, +with or without modifying it, either commercially or noncommercially. +Secondarily, this License preserves for the author and publisher a way +to get credit for their work, while not being considered responsible +for modifications made by others. + + <p>This License is a kind of "copyleft", which means that derivative +works of the document must themselves be free in the same sense. It +complements the GNU General Public License, which is a copyleft +license designed for free software. + + <p>We have designed this License in order to use it for manuals for free +software, because free software needs free documentation: a free +program should come with manuals providing the same freedoms that the +software does. But this License is not limited to software manuals; +it can be used for any textual work, regardless of subject matter or +whether it is published as a printed book. We recommend this License +principally for works whose purpose is instruction or reference. + + </p><li>APPLICABILITY AND DEFINITIONS + + <p>This License applies to any manual or other work, in any medium, that +contains a notice placed by the copyright holder saying it can be +distributed under the terms of this License. Such a notice grants a +world-wide, royalty-free license, unlimited in duration, to use that +work under the conditions stated herein. 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You may include a +translation of this License, and all the license notices in the +Document, and any Warrany Disclaimers, provided that you also include +the original English version of this License and the original versions +of those notices and disclaimers. In case of a disagreement between +the translation and the original version of this License or a notice +or disclaimer, the original version will prevail. + + <p>If a section in the Document is Entitled "Acknowledgements", +"Dedications", or "History", the requirement (section 4) to Preserve +its Title (section 1) will typically require changing the actual +title. + + </p><li>TERMINATION + + <p>You may not copy, modify, sublicense, or distribute the Document except +as expressly provided for under this License. Any other attempt to +copy, modify, sublicense or distribute the Document is void, and will +automatically terminate your rights under this License. However, +parties who have received copies, or rights, from you under this +License will not have their licenses terminated so long as such +parties remain in full compliance. + + </p><li>FUTURE REVISIONS OF THIS LICENSE + + <p>The Free Software Foundation may publish new, revised versions +of the GNU Free Documentation License from time to time. Such new +versions will be similar in spirit to the present version, but may +differ in detail to address new problems or concerns. See +<a href="http://www.gnu.org/copyleft/">http://www.gnu.org/copyleft/</a>. + + <p>Each version of the License is given a distinguishing version number. +If the Document specifies that a particular numbered version of this +License "or any later version" applies to it, you have the option of +following the terms and conditions either of that specified version or +of any later version that has been published (not as a draft) by the +Free Software Foundation. If the Document does not specify a version +number of this License, you may choose any version ever published (not +as a draft) by the Free Software Foundation. + </ol> + +<h3 class="unnumberedsec">ADDENDUM: How to use this License for your documents</h3> + +<p>To use this License in a document you have written, include a copy of +the License in the document and put the following copyright and +license notices just after the title page: + +<pre class="smallexample"> Copyright (C) <var>year</var> <var>your name</var>. + Permission is granted to copy, distribute and/or modify this document + under the terms of the GNU Free Documentation License, Version 1.2 + or any later version published by the Free Software Foundation; + with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. + A copy of the license is included in the section entitled ``GNU + Free Documentation License''. + </pre> + + <p>If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, +replace the "with...Texts." line with this: + +<pre class="smallexample"> with the Invariant Sections being <var>list their titles</var>, with + the Front-Cover Texts being <var>list</var>, and with the Back-Cover Texts + being <var>list</var>. + </pre> + + <p>If you have Invariant Sections without Cover Texts, or some other +combination of the three, merge those two alternatives to suit the +situation. + + <p>If your document contains nontrivial examples of program code, we +recommend releasing these examples in parallel under your choice of +free software license, such as the GNU General Public License, +to permit their use in free software. + + +<div class="contents"> +<h2>Table of Contents</h2> +<ul> +<li><a name="toc_Top" href="#Top">Porting libstdc++</a> +<li><a name="toc_Operating%20system" href="#Operating%20system">Operating system</a> +<li><a name="toc_CPU" href="#CPU">CPU</a> +<li><a name="toc_Character%20types" href="#Character%20types">Character types</a> +<li><a name="toc_Thread%20safety" href="#Thread%20safety">Thread safety</a> +<li><a name="toc_Numeric%20limits" href="#Numeric%20limits">Numeric limits</a> +<li><a name="toc_Libtool" href="#Libtool">Libtool</a> +<li><a name="toc_GNU%20Free%20Documentation%20License" href="#GNU%20Free%20Documentation%20License">GNU Free Documentation License</a> +<ul> +<li><a href="#GNU%20Free%20Documentation%20License">ADDENDUM: How to use this License for your documents</a> +</li></ul> +</li></ul> +</div> + + </body></html> + |
